WARSAW, May 15 (Reuters) - Poland’s biggest power group PGE on Tuesday reported a net profit of 935 million zlotys ($258.39 million) in the first quarter, 3 percent down year on year and slightly lower than the utility’s estimate of 959 million zlotys.

State-run PGE, which generates 56 percent of its electricity from lignite, also said the group’s total power production rose 18 percent to 17.7 terawatt hours (TWh) in the first quarter.

PGE said that electricity consumption rose by 2.8 percent year on year in the first quarter, while the average price of electricity on the day-ahead market increased by 19 percent to 184 zlotys per megwatt hour (MWh).

The company said that Poland’s electricity imports grew to 1.59 TWh in the first three months of 2018 from 0.22 TWh a year ago. ($1 = 3.6186 zlotys) (Reporting by Agnieszka Barteczko. Editing by Jane Merriman)